Claisen Condensation(ngưng tụ claisen)

<h2 style="font-family: Arial, Helvetica, 'sans serif'; font-size: 12pt; margin-bottom: 20px; margin-top: 20px;"></h2><h2><i>Acetoacetic-Ester Condensation</i></h2><h2><i>Claisen Condensation</i></h2><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEnkP4E8B2yHNhNiR4kOeDTD-0Tn4aGBPZktp48wzOdjdcjq5MiQiVSz8Ff4SSCpg0RCwt522VTRqRW_uxYwAjb462m5Erv_7M-QEH-LTk_Sfz2KsD0gm6E99MADaix0ePZWrQo_7xXdQ/s1600/claisen.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="Claisen Condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEnkP4E8B2yHNhNiR4kOeDTD-0Tn4aGBPZktp48wzOdjdcjq5MiQiVSz8Ff4SSCpg0RCwt522VTRqRW_uxYwAjb462m5Erv_7M-QEH-LTk_Sfz2KsD0gm6E99MADaix0ePZWrQo_7xXdQ/s1600/claisen.gif" title="Claisen Condensation" /></a></div><div><h4>Summary</h4><ul><li>The Claisen condensation is the ester analogue of the <b><i>Aldol condensation</i></b>.</li><li>Reagents : most commonly the base would be the alkoxide, <b>R'O^{-<a name="more"></a>}</b></li><li>The reaction involves an ester enolate reacting with another molecule of the ester.</li><li>Remember enolates are good nucleophiles and the ester carbonyl <b>C</b> are electrophilic.</li><li>The products of these reactions are <b><i><span style="font-family: Symbol;">b-</span>ketoesters</i></b> which are important, useful synthetic intermediates.</li><li>Note that the product is the original ester with an acyl group added <i>i.e.</i> an <b>acylation</b> reaction has occurred.</li><li>A simple example of a Claisen condensation is the reaction of ethyl ethanoate which is shown below in two representations:</li></ul></div><h1><img alt="Claisen condensation" height="53" src="http://www.organic-chemistry.org/namedreactions/claise14.gif" style="border: 0px; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;" title="Claisen condensation" width="333" /></h1><h1><div><div class="MsoNormal" style="font-family: Arial, Helvetica, 'sans serif';"><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;">The </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt;"><i>Claisen Condensation </i></span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;">between esters containing α-hydrogens, promoted by a base such as sodium ethoxide, affords </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt;"><i>β-ketoesters</i>.</span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;"> The driving force is the formation of the stabilized anion of the </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt;"><i>β-keto ester</i>.</span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;"> If two different esters are used, an essentially statistical mixture of all four products is generally obtained, and the preparation does not have high synthetic utility.<o:p></o:p></span></div><div class="MsoNormal" style="font-family: Arial, Helvetica, 'sans serif';"><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;">However, if one of the ester partners has enolizable α-hydrogens and the other does not (e.g., aromatic esters or carbonates), the mixed reaction (or crossed Claisen) can be synthetically useful. If ketones or nitriles are used as the donor in this </span><i><span style="font-family: 'Times New Roman', serif; font-size: 12pt;">condensation </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt;">reaction</span></i><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;">, a β-diketone or a β-ketonitrile is obtained, respectively.<o:p></o:p></span></div><div class="MsoNormal" style="font-family: Arial, Helvetica, 'sans serif';"><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal;">The use of stronger bases, e.g. sodium amide or sodium hydride instead of sodium ethoxide, often increases the yield.<o:p></o:p></span></div><div style="font-family: Arial, Helvetica, 'sans serif';"><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal; line-height: 115%;">The </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; line-height: 115%;"><i>intramolecular</i></span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal; line-height: 115%;"> version is known as</span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; font-weight: normal; line-height: 115%;"> </span><span style="font-family: 'Times New Roman', serif; font-size: 12pt; line-height: 115%;"><span style="color: #5a3696; line-height: 115%;"><a href="http://www.organic-chemistry.org/namedreactions/dieckmann-condensation.shtm" rel="nofollow" target="_blank"><i>DieckmannCondensation</i></a></span></span></div><h4 style="font-family: Arial, Helvetica, 'sans serif';"><span style="font-family: 'Times New Roman', serif; font-size: large; line-height: 115%;">Translate to Vietnamese:</span></h4><div><span style="font-family: Times New Roman, serif; font-size: small;"><span style="line-height: 18.399999618530273px;"> <span style="font-weight: normal;">Hiểu sơ bộ:</span></span></span></div></div><div><ul><li><span style="font-size: small;"><span style="font-weight: normal;">Là phản ứng giữa 2 ester có </span></span><span style="font-family: 'Times New Roman', serif; font-size: 16px; font-weight: normal;">α-hydrogen</span></li><li><span style="font-family: 'Times New Roman', serif; font-size: 16px; font-weight: normal;">Xúc tác: base như EtONa, MeONa,NaNH2,NaH</span></li><li><span style="font-family: 'Times New Roman', serif; font-size: 16px; font-weight: normal;">Tạo ra sản phẩm trung gian ổn định: anion của </span><span style="font-family: 'Times New Roman', serif; font-size: 16px;"><i>β-keto ester</i></span></li><li><span style="font-family: Times New Roman, serif; font-size: small;"><span style="font-weight: normal;">Sản phẩm tạo ra là </span></span><span style="font-family: 'Times New Roman', serif; font-size: 16px;"><i>β-keto ester</i></span></li><li><span style="font-family: Times New Roman, serif; font-size: small;"><span style="font-weight: normal;">Khi 2 ester là khác nhau: tạo ra một hỗn hợp 4 sản phẩm </span></span><span style="font-family: 'Times New Roman', serif; font-size: 16px;"><i>β-keto ester</i></span></li></ul></div></h1><h3 style="font-family: Arial, Helvetica, 'sans serif'; margin-bottom: 0px; margin-top: 0px;"><span style="font-size: large;"><i>Mechanism of the Claisen Condensation</i></span></h3><h1><div style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;"><img alt="Mechanism of the Claisen Condensation" height="74" src="http://www.organic-chemistry.org/namedreactions/claise16.gif" style="border: 0px;" title="Mechanism of the Claisen Condensation" width="459" /></div><div style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;"><img alt="Mechanism of the Claisen Condensation" height="81" src="http://www.organic-chemistry.org/namedreactions/claise17.gif" style="border: 0px;" title="Mechanism of the Claisen Condensation" width="400" /></div><div><div style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;"><img alt="Mechanism of the Claisen Condensation" height="57" src="http://www.organic-chemistry.org/namedreactions/claise15.gif" style="border: 0px;" title="Mechanism of the Claisen Condensation" width="628" /></div><div style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;"><br /></div><h3><i style="font-family: Arial, Helvetica, 'sans serif'; font-size: x-large;"><u>Example</u></i></h3><h3><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: large; font-weight: normal;">1.</span></h3></div></h1><h1><div><div class="separator" style="clear: both; font-family: Arial, Helvetica, 'sans serif'; font-weight: normal; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZ9nutjkeGlfGoqOsEGUSn5hmprv6_MLNV1rrWox-Z_zR71zkbPCcnMvQT6rf_KAH6no320AoYuAlsSX8EV0_AvG7aur4PncaXFdKRwoXbO7s9dRBjK3EW3BVDRZYemMHHDrH73h6jgqc/s1600/claisen+condensation+2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhZ9nutjkeGlfGoqOsEGUSn5hmprv6_MLNV1rrWox-Z_zR71zkbPCcnMvQT6rf_KAH6no320AoYuAlsSX8EV0_AvG7aur4PncaXFdKRwoXbO7s9dRBjK3EW3BVDRZYemMHHDrH73h6jgqc/s1600/claisen+condensation+2.gif" title="claisen condensation" /></a></div><div style="font-family: Arial, Helvetica, 'sans serif'; font-weight: normal;"><span style="font-size: large;"><br /></span></div><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="font-family: Arial, Helvetica, 'sans serif'; font-weight: normal; margin-left: auto; margin-right: auto; text-align: center;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgw43XSEqY6rLxY5MJ4wDYUpNh6MlhD98RSzeJ9Dmo57JOSzNlT-JqTYlnILR03ry17K9yknYkCyH6RV1CEn9TqL-pDIokpbidxVwahNkTVPWEDPh8pePJsgD5EKu277ik9LodornuNeno/s1600/claisen+condensation.gif" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgw43XSEqY6rLxY5MJ4wDYUpNh6MlhD98RSzeJ9Dmo57JOSzNlT-JqTYlnILR03ry17K9yknYkCyH6RV1CEn9TqL-pDIokpbidxVwahNkTVPWEDPh8pePJsgD5EKu277ik9LodornuNeno/s1600/claisen+condensation.gif" title="claisen condensation" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><b><i>claisen condensation </i></b></td></tr></tbody></table><div class="separator" style="clear: both; font-family: Arial, Helvetica, 'sans serif'; font-weight: normal; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibM6zL68x0rgjkO-FFge9mbk8w8Xwy_9zVzHrdqNTK6mVYBBzGD6en1LnhHrFSUT2oD6eNxjA8rcOHkeJYB0WTz0hJY9kBACVJx1ps1a_V-A-wf0RjDs3HAiiBvf79EGp1ziq8Rl2eusc/s1600/claisen+condensation+1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibM6zL68x0rgjkO-FFge9mbk8w8Xwy_9zVzHrdqNTK6mVYBBzGD6en1LnhHrFSUT2oD6eNxjA8rcOHkeJYB0WTz0hJY9kBACVJx1ps1a_V-A-wf0RjDs3HAiiBvf79EGp1ziq8Rl2eusc/s1600/claisen+condensation+1.gif" title="claisen condensation" /></a></div><div style="font-family: Arial, Helvetica, 'sans serif'; font-weight: normal;"><span style="background-color: white; font-size: 13px;">General, Robust, and Stereocomplementary Preparation of α,β-Disubstituted α,β-Unsaturated Esters</span><br /><span style="background-color: white; font-size: 13px;">H. Nakatsuji, H. Nishikado, K. Ueno, Y. Tanabe, </span><i style="background-color: white; font-size: 13px;">Org. Lett.</i><span style="background-color: white; font-size: 13px;">, </span><b style="background-color: white; font-size: 13px;">2009</b><span style="background-color: white; font-size: 13px;">, </span><i style="background-color: white; font-size: 13px;">11</i><span style="background-color: white; font-size: 13px;">, 4258-4261.</span></div><div style="font-family: Arial, Helvetica, 'sans serif'; font-weight: normal;"><span style="background-color: white; font-size: 13px;"><br /></span></div><h4 style="font-family: Arial, Helvetica, 'sans serif';"><span style="background-color: white;"><span style="font-size: large;">Translate to Vietnamese:</span></span></h4><div><ul><li><span style="font-family: Arial, Helvetica, sans serif; font-size: small;"><span style="font-weight: normal;">NEt3(TEA): Triethylamin, là xúc tác base</span></span></li><li><span style="font-family: Arial, Helvetica, sans serif; font-size: small;"><span style="font-weight: normal;">TiCl4: vai trò phản ứng với EtOH tạo ra, thúc đẩy phản ứng xảy ra theo chiều thuận.<br />TiCl4 + 4EtOH -----------------> Ti(OC2H5)4 + 4 HCl</span></span></li><li><span style="font-family: Arial, Helvetica, sans serif; font-size: small;"><span style="font-weight: normal;">Dung môi CH2Cl2 hoặc toluen: Phải dùng dung môi hòa tan cả 2 chất phản ứng, tạo nên hệ đồng thể thì hiệu suất mới cao( nói đúng hơn phản ứng mới xảy ra)</span></span></li></ul></div><h4 style="font-family: Arial, Helvetica, 'sans serif'; font-weight: normal;"><span style="background-color: white;"><span style="font-size: large;">2.</span></span></h4></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-Na_glRLdo6ET6U7hbVC1hpmi_RZgiqBKcUYV3Qf-7j9omKqrIMqlyt2cDwaIxQmD2c5HbK0Ok49s0OZETZUqMslBL5Z0JqPqWJIHRaBu-munDmCamb-dT4BHklf3cn27OZmcWzdsp3s/s1600/claisen+condensation+1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-Na_glRLdo6ET6U7hbVC1hpmi_RZgiqBKcUYV3Qf-7j9omKqrIMqlyt2cDwaIxQmD2c5HbK0Ok49s0OZETZUqMslBL5Z0JqPqWJIHRaBu-munDmCamb-dT4BHklf3cn27OZmcWzdsp3s/s1600/claisen+condensation+1.gif" title="claisen condensation" /></a></div> <b style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">Abstract</b><br /><div style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;"><span style="font-weight: normal;">Thioesters undergo chemoselective soft enolization and acylation by <i>N</i>-acylbenzotriazoles on treatment with MgBr<sub style="line-height: 1;">2</sub>·OEt<sub style="line-height: 1;">2</sub> and <i>i </i>-Pr<sub style="line-height: 1;">2</sub>NEt to give β-keto thioesters without prior enolate formation. The reaction is conducted using untreated CH<sub style="line-height: 1;">2</sub>Cl<sub style="line-height: 1;">2</sub> open to the air. The coupled products can be converted directly into </span><i>β-keto esters</i><i>, β-keto amides, </i><span style="font-weight: normal;">and</span><i> β-diketones</i><span style="font-weight: normal;"> under mild conditions.</span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4aFKpON1PxvdqKUJ4yPArhlJaM7kBpYSnbGz9JqFZEvTxoBqkeJNyhrqM4ZHWqXNh0HVy81rfHsfCadtFH6-EcPaiENOWWBSIEGtfwI_Wqowkkgc3ICToqZjk8PTwAbVRR1vPAe3ciQ4/s1600/claisen+condensation2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4aFKpON1PxvdqKUJ4yPArhlJaM7kBpYSnbGz9JqFZEvTxoBqkeJNyhrqM4ZHWqXNh0HVy81rfHsfCadtFH6-EcPaiENOWWBSIEGtfwI_Wqowkkgc3ICToqZjk8PTwAbVRR1vPAe3ciQ4/s1600/claisen+condensation2.gif" title="claisen condensation" /></a></div><div class="separator" style="clear: both; text-align: center;"><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">Direct Carbon-Carbon Bond Formation via Chemoselective Soft Enolization of Thioesters: A Remarkably Simple and Versatile Crossed-Claisen Reaction Applied to the Synthesis of LY294002</span></div><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">G. Zhou, D. Lim, D. M. Coltart, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">Org. Lett.</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; text-align: start;">2008</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">10</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal; text-align: start;">, 3809-3812.</span><br /> </h1><h4 style="font-family: Arial, Helvetica, 'sans serif'; font-size: 32px;"><span style="background-color: white;"><span style="font-size: large;">Translate to Vietnamese:</span></span></h4><div><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">MgBr</span><sub style="font-family: Arial, Helvetica, 'sans serif'; line-height: 1;">2</sub><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">·OEt</span><sub style="font-family: Arial, Helvetica, 'sans serif'; line-height: 1;">2 </sub><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">and</span><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;"> </span><i style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">i </i><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">-Pr</span><sub style="font-family: Arial, Helvetica, 'sans serif'; line-height: 1;">2</sub><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">NEt có vai trò: tránh tạo ra enolate.</span></div><div><span style="font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;"><br /></span></div><h1><div><span style="background-color: white;"><span style="font-size: large;">3.</span></span></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFekHR_XTW-reyozGQ0SMnmwmcwKhAkmQJ-rqJvgAbZ2y5aUqu5l0vFSbN78B6ClOZpC2Uy33tjNjDdvFqcQr4Ts_utwhY7dia8L2eWBIVfD3RX8eQz3WDqHJLHrGJ7lFrQfY2P9o0iuk/s1600/1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFekHR_XTW-reyozGQ0SMnmwmcwKhAkmQJ-rqJvgAbZ2y5aUqu5l0vFSbN78B6ClOZpC2Uy33tjNjDdvFqcQr4Ts_utwhY7dia8L2eWBIVfD3RX8eQz3WDqHJLHrGJ7lFrQfY2P9o0iuk/s1600/1.gif" title="claisen condensation" /></a></div><br /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Mild and Efficient Pentafluorophenylammonium Triflate (PFPAT)-Catalyzed C-Acylations of Enol Silyl Ethers or Ketene Silyl (Thio)Acetals with Acid Chlorides</span><br style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;" /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">A. Iida, J. Osada, R. Nagase, T. Misaki, Y. Tanabe, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Org. Lett.</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">2007</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">9</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, 1859-1862.</span><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-zvOWZ0rPxpa4M44DreOJqcVX59aZ_L4CotSAVL6uQM9XE8pQK9Vnupe-_XfWw1OudRMed2xi6gkdsf6IfhFfACNjsk5fEpSSM-INWCcxOzaLZ8ICp_dldq6uQaWcQXSV5h83JBdRccQ/s1600/2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-zvOWZ0rPxpa4M44DreOJqcVX59aZ_L4CotSAVL6uQM9XE8pQK9Vnupe-_XfWw1OudRMed2xi6gkdsf6IfhFfACNjsk5fEpSSM-INWCcxOzaLZ8ICp_dldq6uQaWcQXSV5h83JBdRccQ/s1600/2.gif" title="claisen condensation" /></a></div><br /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Powerful Ti-Crossed Claisen Condensation between Ketene Silyl Acetals or Thioacetals and Acid Chlorides or Acids</span><br style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;" /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">A. Iida, S. Nakazawa, T. Okabayashi, A. Horii, T. Misako, Y. Tanabe, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Org. Lett.</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">2006</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">8</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, 5215-5218.</span><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYCZO5U7uEIc2tExk4npbIxAyAzSg2c5vB_160I3OMOEUJJ_-YNZE-70Ze5a2aM4eYJWRgeoZVLV_v_hUWnODNE26MiZRj105yUBbdiNb8somheUKN2Q0oBDI-0wpRsrYU9eCz9bbLoVQ/s1600/3.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYCZO5U7uEIc2tExk4npbIxAyAzSg2c5vB_160I3OMOEUJJ_-YNZE-70Ze5a2aM4eYJWRgeoZVLV_v_hUWnODNE26MiZRj105yUBbdiNb8somheUKN2Q0oBDI-0wpRsrYU9eCz9bbLoVQ/s1600/3.gif" title="claisen condensation" /></a></div><br /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Synthesis of Trifluoromethyl Ketones via Tandem Claisen Condensation and Retro-Claisen C-C Bond-Cleavage Reaction</span><br style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;" /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">D. Yang, Y. Zhou, N. Xue, J. Qu, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">J. Org. Chem.</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">2013</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">78</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, 4171-4176.</span><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnPpHcD2MrlWXcFAaNXkrJsEDHXmOo2iDI0NHvEpZwxGC5wxyfb3tR7GkQRHnM_o_mp0Pyl4aBohTiSNHwso4k1i8Xn8Rgr-UoHWO052jFu53boXDwkexukQDD4HGl3Rg-On2bqhx61lw/s1600/4.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnPpHcD2MrlWXcFAaNXkrJsEDHXmOo2iDI0NHvEpZwxGC5wxyfb3tR7GkQRHnM_o_mp0Pyl4aBohTiSNHwso4k1i8Xn8Rgr-UoHWO052jFu53boXDwkexukQDD4HGl3Rg-On2bqhx61lw/s1600/4.gif" title="claisen condensation" /></a></div><br /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Consecutive </span><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;"><i>Michael</i></span><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">-</span><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;"><i>Claisen </i></span><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Process for Cyclohexane-1,3-dione Derivative (CDD) Synthesis from Unsubstituted and Substituted Acetone</span><br style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;" /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">D. Sharma, Bandna, A. K. Shil, B. Singh, P. Das, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Synlett</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">2012</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">23</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, 1199-1204.</span><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5RBiywnwCbjQ_xR2a0i-NZ6I13bbxJVqzMSJ9IiRkXYN8i6i23zfgzwJsvah_s3lqkU_YhdT5FFa2YeayRIJZaZtGE0H54WOWzZNWHv9sHr7P0PZ8q2yFoGzc3W2PLGbtTc_IGSswBoc/s1600/5.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="claisen condensation" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5RBiywnwCbjQ_xR2a0i-NZ6I13bbxJVqzMSJ9IiRkXYN8i6i23zfgzwJsvah_s3lqkU_YhdT5FFa2YeayRIJZaZtGE0H54WOWzZNWHv9sHr7P0PZ8q2yFoGzc3W2PLGbtTc_IGSswBoc/s1600/5.gif" title="claisen condensation" /></a></div><div><span style="background-color: white;"><span style="font-size: large;"><br /></span></span></div><div><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">"One-Pot" Synthesis of 4-Substituted 1,5-Diaryl-1</span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">H</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">-pyrazole-3-carboxylic Acids via a MeONa/LiCl-Mediated Sterically Hindered Claisen Condensation-Knorr Reaction-Hydrolysis Sequence</span><br /><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">J.-A. Jiang, C.-Y. Du, C.-H. Gu, Y.-F. Ji, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">Synlett</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><b style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px;">2012</b><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, </span><i style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">23</i><span style="background-color: white; font-family: Arial, Helvetica, 'sans serif'; font-size: 13px; font-weight: normal;">, 2965-2968.</span></div></h1>

Claisen Condensation(ngưng tụ claisen)

Acetoacetic-Ester Condensation Claisen Condensation Summary The Claisen condensation is the ester analogue of the  Aldol condensation . Reag...

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Reaction of nitro compounds-Phản ứng nitro hóa

<h2><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span style="background-color: white;">Bài 1:Reaction of nitro compounds -Phản ứng nitro hóa</span></h2><div class="separator" style="clear: both; text-align: center;"></div><div><div class="separator" style="clear: both; text-align: center;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="phản ứng nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHnS2jDKXOYwj_oXibv4afUFOX-M1CNcEaP5mbPqPpZX-GbpndZm9IBR61N57rUbjr05NcAaYCrP2p2zsQ84YcmQwAMUluSFdsb_Qpai-lgzVvLl19reXwr_N31Y5Gfac0EkEbiGiYAmc/s1600/nitro+hoa.jpg" title="phản ứng nitro hóa" /></a></div><span style="background-color: white;"><br /></span></div><div><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><span style="background-color: white;">Nitro hóa là quá trình hóa học nhằm thay thế một hoặc nhiều nguyên tử Hydro của hợp chất hữu cơ bằng một hay nhiều nhóm thế Nitro(-NO₂)</span><br /><a href="https://www.blogger.com/null" name="more"></a></div><h3><span style="background-color: white;">I. Cơ chế phản ứng</span></h3><div class="separator" style="clear: both; text-align: center;"><span style="background-color: white;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></span></div><h4><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><span style="background-color: white;">I.1: Electropphilic Substitution( Cơ chế thế ái điện tử)</span></h4><div><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><span style="background-color: white;">-<b><i>Nitro hóa</i></b> hợp chất thơm (Aromatic compounds)</span></div><div><blockquote class="tr_bq"><span style="background-color: white;">-Tác nhân : hỗn hợp sulfo-nitric [1], tác nhân electrophile là -NO₂^{+   <img src="http://us.i1.yimg.com/us.yimg.com/i/mesg/emoticons7/21.gif" />} </span></blockquote></div><div><span style="background-color: white;">-Phản ứng thực hiện ở pha lỏng, nhiệt độ thường không cao</span></div><div><span style="background-color: white;">-Cơ chế ái điện tử <b><img /><span style="color: red;">S_E</span></b></span><br /><span style="background-color: white;">-Tác nhân -NO₂⁺ được tạo thành theo phương trình sau:</span><br /><span style="background-color: white;"><br /></span></div><div class="separator" style="clear: both; text-align: center;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="phản ứng nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuZyXE8YZix5dJiu8rpphmK6zhab3Az-AncY7bdPi3iurv9C5KxDGPiDqMBPo7sp4UI2dSSn9SSy9xCLP5bIuDYUfMiefQ09YHpOSsvLYnR3qZxmi7PeiiOl_kjw2PBKnSzGwOxnm_HiI/s1600/nitro+hoa+2.gif" title="phản ứng nitro hóa" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><div class="" style="clear: both; text-align: left;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><b style="background-color: white;">-Cơ chế thế ái điện tử( The electrophilic substitution mechanism)[<span style="color: red;">2</span>]</b></div><div style="font-family: Helvetica, Arial;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><b><i style="background-color: white;">Stage one(Giai đoạn 1)</i></b></div><div style="font-family: Helvetica, Arial;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><span style="background-color: white;">ion -NO₂⁺ tấn công vào nhân thơm theo cơ chế ái điện tử tạo phức sigma <b style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;">σ</b></span><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="phản ứng nitro hóa" border="0" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHGrgyrspez8WkNdL5ggtyPpaQxENGguj_ONUA6mzdf76WTfZBQOLFoEUMg6ojE_dXoRyS-hrnS40btrU_VZywrgwBKnEZCxuFkZawxahGdlyw2X570jxT328OS3jzle0XPwa8g-TT4UY/s1600/nitratem1+(FILEminimizer).png" title="phản ứng nitro hóa" width="320" /></a></div><span style="background-color: white;"><b style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;"><br /></b></span></div><div align="center" style="font-family: Helvetica, Arial;"><div class="separator" style="clear: both; text-align: center;"><span style="background-color: white;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a></span></div><div class="separator" style="clear: both; text-align: center;"></div><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><br /></div><div style="font-family: Helvetica, Arial;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><b><i style="background-color: white;">Stage two(Giai đoạn 2)</i></b><br /><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><br /><div class="separator" style="clear: both; text-align: center;"><b><i style="background-color: white;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="phản ứng nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOT-bmiT9LnXK8mZIpyG63unjpl8dstFudRX-N0yS7AlU9vDNCXJhWSwWT0tmabU6K0vGu12M4pnpeHeSCXOM1olYi-1Y99hli7_nI6ZN0CbEcz0TPxgVqBbDkG87f9YzhXsXKnuzvdr4/s1600/nitro+hoa+3.png" title="phản ứng nitro hóa" /></a></i></b></div></div><div align="center"><div style="font-family: Helvetica, Arial;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"></a><br /></div><div style="text-align: left;"><div style="font-family: Helvetica, Arial;"><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><a href="https://www.blogger.com/blogger.g?blogID=8923186954726478298" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a><span style="background-color: white;">-Vai trò:</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"><b><span style="font-family: Times New Roman; font-size: 14px;">H₂SO₄</span> </b>là xúc tác tạo ion nitroni và tạo ra môi trường acid đủ mạnh để ngăn cản sự phân ly của acid nitric thành H⁺ và NO₃^- . Khi nồng độ H₂SO₄ giảm thì tốc độ phản ứng nitro hóa cũng giảm theo</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">    <i>Ví dụ: </i></span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"><br />Khi nitro hóa <b>benzen</b> ở 25 độ C , nếu nồng độ <b>acid sulfuric</b> nhỏ hơn 80% thì phản ứng xảy ra không đáng kể. Nếu nồng độ <b>acid sulfuric</b> là 80-90% thì tốc độ phản ứng tăng lên 1000 lần.</span></div><h4 style="font-family: Helvetica, Arial;"><span style="background-color: white;">I.2: Radical Substitution (Cơ chế thế gốc tự do)</span></h4><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Nitro hóa<b> Hydrocarbon no</b> mạch thẳng</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Tác nhân <b>acid HNO</b>_<b>3</b></span><br /><span style="background-color: white;">loãng( 30-40%)</span><br /><span style="background-color: white;">-Phản ứng thực hiện ở thể khí</span><br /><span style="background-color: white;">-Nhiệt độ cao (300-500 độ C)</span><br /><span style="background-color: white;">-Nhược điểm: ngoài sản phẩm chính còn thu được hỗn hợp các <b>sản phẩm oxy hóa, alcol, hydrocarbon</b> khác...</span><br /><span style="background-color: white;">-Cơ chế gốc tự do:</span><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="phản ứng nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYhECLiMJZh_BJhwHrYgH3viOvE8nIj127Ur6iX1pdpSBxo5rJm_0_hyphenhyphenIcwz8NTqUey0na_DqU_zHghGbEeldKGeI6ecxNWBzFA_DMT-FodlTg69yx2A3eE_ets-29ZDb1YNhunE_HrHU/s1600/nitro+hoa+4.gif" title="phản ứng nitro hóa" /></a></div><span style="background-color: white;"><br /></span><br /><div class="separator" style="clear: both; text-align: center;"></div><div style="text-align: right;"></div><h3><span style="background-color: white;"> II. Tác nhân nitro hóa</span></h3></div><div style="font-family: Helvetica, Arial;"><h4><span style="background-color: white;">II.1: Acid nitric(HNO₃)</span></h4></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Dạng tinh khiết  là chất lỏng trong, mùi hắc mạnh, sôi ở 85,3 độ C, d=1,502. Đun sôi hay để lâu ngoài ánh sáng bị phân hủy:</span></div><div style="font-family: Helvetica, Arial; text-align: center;"><span style="background-color: white;"><span style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;">4 HNO</span><sub style="color: #252525; font-family: sans-serif; line-height: 1;">3</sub><span style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;"> → 2 H</span><sub style="color: #252525; font-family: sans-serif; line-height: 1;">2</sub><span style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;">O + 4 NO</span><sub style="color: #252525; font-family: sans-serif; line-height: 1;">2</sub><span style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;"> + O</span><sub style="color: #252525; font-family: sans-serif; line-height: 1;">2</sub><span style="color: #252525; font-family: sans-serif; font-size: 14px; line-height: 22.399999618530273px;">.</span></span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Công nghiệp hay dùng nồng độ: 65-68% , 95% (bốc khói).</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Nồng độ cao đựng trong bình thủy tinh sành hoặc Nhôm, tránh ánh sáng</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Nồng độ thấp đựng trong bình thủy tinh, sành, thép không gỉ, tránh ánh sáng</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Là tác nhân nitro hóa yếu vì bị pha loãng bởi nước tạo thành trong quá trình phản ứng.</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">- Có tính oxy hóa mạnh -> tạo nhiều tạp chất là sản phẩm oxy há Hydrocarbon</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Lượng acid nitric dùng cho phản ứng nitro hóa khoảng 1,5-2 lần so với lý thuyết</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"><br /></span><br /><h4><span style="background-color: white;">II.2: Hỗn hợp sulfo-nitric</span></h4><span style="background-color: white;">-ưu điểm:</span><br /><span style="background-color: white;">   +tính oxy hóa yếu hơn <b>acid nitric</b> , do đó ít tạo sản phẩm phụ hơn;</span><br /><span style="background-color: white;">   +tạo tác nhân nitro hóa mạnh hơn</span><br /><span style="background-color: white;">   +Tránh tạo thành dẫn chất <span style="color: red;"><b>polynitro</b></span></span><br /><span style="background-color: white;">-tác nhân nitroni tạo thành theo phương trình:</span><br /><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuZyXE8YZix5dJiu8rpphmK6zhab3Az-AncY7bdPi3iurv9C5KxDGPiDqMBPo7sp4UI2dSSn9SSy9xCLP5bIuDYUfMiefQ09YHpOSsvLYnR3qZxmi7PeiiOl_kjw2PBKnSzGwOxnm_HiI/s1600/nitro+hoa+2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuZyXE8YZix5dJiu8rpphmK6zhab3Az-AncY7bdPi3iurv9C5KxDGPiDqMBPo7sp4UI2dSSn9SSy9xCLP5bIuDYUfMiefQ09YHpOSsvLYnR3qZxmi7PeiiOl_kjw2PBKnSzGwOxnm_HiI/s1600/nitro+hoa+2.gif" title="phản ứng nitro hóa" /></a></div><span style="background-color: white;"><br /></span><span style="background-color: white;">-Tỷ lệ hỗn hợp <b>H₂SO₄ : HNO₃: H₂O</b> phụ thuộc vào bản chất cuả chất được nitro hóa:</span><br /><span style="background-color: white;">  + Các hợp chất thơm có khả năng phản ứng cao( <b>phenol, phenol -ether</b>) chỉ cần dùng dung dịch<b> HNO₃</b> 40%.</span><br /><span style="background-color: white;">  +Các hợp chất thơm có khả năng phản ứng trung bình( phần lớn nhóm thế loại 1, trừ <b>dẫn xuất Halogen</b>) thì để <b>nitro hóa</b> 1 mol, cần 1,5 mol <b>HNO₃</b> 68% và 2,2 mol <b>H₂SO₄</b></span><br /><span style="background-color: white;">98%.</span><br /><span style="background-color: white;">  +Các hợp chất thơm có khả năng phản ứng thấp( Các nhóm thế loại 2) thì để nitro hóa 1 mol cần 2,3 mol <b>HNO₃</b> 95-100% và 2,6 mol <b>H₂SO₄</b></span><br /><span style="background-color: white;">98%.</span><br /><span style="background-color: white;">-Công nghiệp thường pha sẵn :</span><br /><span style="background-color: white;">  + <b>HNO₃</b> 88% và <b>H₂SO₄</b></span><br /><span style="background-color: white;">95% và <b>H₂O</b> 2,5%</span><br /><h4><span style="background-color: white;">II.3: Muối nitrat và acid sulfuric</span></h4><span style="background-color: white;">-Nitro hóa trong môi trường khan nước</span><br /><span style="background-color: white;">-thường được sử dụng để điều chế các dẫn chất polynitro:</span><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguqZdAqbgTseVGZOfVSm8U4idm3VyW3zuRA4mPfcX_u8vJ3BQVF3JdmFAxeK0r2d94MkaLDT-Sn30kLHtTUFpBRYxiwtFTRU7BPapnb1w6A0_NtbtAvShJSfP4-5ydqllLI-4vYG19wSg/s1600/nitro+hoa+5.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img alt="nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguqZdAqbgTseVGZOfVSm8U4idm3VyW3zuRA4mPfcX_u8vJ3BQVF3JdmFAxeK0r2d94MkaLDT-Sn30kLHtTUFpBRYxiwtFTRU7BPapnb1w6A0_NtbtAvShJSfP4-5ydqllLI-4vYG19wSg/s1600/nitro+hoa+5.gif" title="nitro hóa" /></a></div><span style="background-color: white;"><br /></span><br /><div class="separator" style="clear: both; text-align: left;"><span style="background-color: white;"><br /></span></div><span style="background-color: white;">- Ví dụ trong tổng hợp TNT:</span><br /><div class="separator" style="clear: both; text-align: center;"><a href="http://quanghai.name.vn/" rel="nofollow" target="_blank"><img alt="sự nitro hóa" border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiE95aPzxKZwNhVBv6r7H-jvA14tsBwkJvMq2gDWb_QMZnjAtxZSI8nwiH99cpx1tz7mFsePVkx5ys-JCyHybV-ug4ybJIZDLULS53mt6sMaeA7XyJWcccTxZg_UUgO0pCwMK80jF3HGDY/s1600/nitro+hoa+6.gif" title="sự nitro hóa" /></a></div><span style="background-color: white;"><br /></span><br /><div class="separator" style="clear: both; text-align: left;"><span style="background-color: white;">    +Hỗn hợp acid : <b>HNO₃</b> 99%/ <b>CH₃Cl</b> +  <b>H₂SO₄</b>  99%</span></div><div class="separator" style="clear: both; text-align: left;"><span style="background-color: white;">trong đó : <b>HNO₃</b> được tạo ra bàng phản ứng giữa <b>KNO₃</b> or <b>NaNO₃</b> với <b>H₂SO₄</b> ở 0 độ C. </span></div><div class="separator" style="clear: both; text-align: left;"><span style="background-color: white;">     +Xem tài liệu sau( trang 5): <a href="http://forum-chemistry.blogspot.com/2014/08/preparation-of-tnt-tnt-synthesis.html" target="_blank">TNT synthesis</a></span></div><h4 style="clear: both; text-align: left;"><span style="background-color: white;">II.4:Acylnitrat (AcONO2)</span></h4></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Là tác nhân nitro hóa mạnh</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Dùng để nitro hóa các chất dễ bị phân hủy bởi nước hoặc acid vô cơ</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Sản phẩm phụ của phản ứng là Acid acetic</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"><br /></span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5JG55D9XtYNCoAFeLjX92uy4PC3jP4PZTCwFkTKIDpzjX6hxPjNOBfMaRnX_wmG_4CtbaCzL4BS72oOGrOqmD4yo6eZ8HxwqxBzWk1zdNne7hZU6z2uzQtePwfbMW7Gg-Z1mRqYX3A5k/s1600/acylnitrat.bmp" imageanchor="1" style="background-color: white; margin-left: 1em; margin-right: 1em;"><img alt="Acylnitrat" border="0" height="85" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi5JG55D9XtYNCoAFeLjX92uy4PC3jP4PZTCwFkTKIDpzjX6hxPjNOBfMaRnX_wmG_4CtbaCzL4BS72oOGrOqmD4yo6eZ8HxwqxBzWk1zdNne7hZU6z2uzQtePwfbMW7Gg-Z1mRqYX3A5k/s1600/acylnitrat.bmp" title="Acylnitrat" width="400" /></a></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">  Khi dùng tác nhân bày nitro hóa các amine thơm, đồng thời quá trình nitro hóa nhóm amine thơm cũng được bảo vệ:</span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7SpdqMBSXcid2K84hAD7IgdDa98tv0XeUuKCymGwInx1qtFIwrn0v6JDCdRNml0d2LHdbk6rFmiioldYRokLORvCE8XLijaRc5VT8mME00GrRAXn-zxMGnR6vXMIAsayiKHnIoVBDrNg/s1600/nitro+h%C3%B3a+amine+thom.bmp" imageanchor="1" style="background-color: white; margin-left: 1em; margin-right: 1em;"><img alt="nitro hóa amine thơm" border="0" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7SpdqMBSXcid2K84hAD7IgdDa98tv0XeUuKCymGwInx1qtFIwrn0v6JDCdRNml0d2LHdbk6rFmiioldYRokLORvCE8XLijaRc5VT8mME00GrRAXn-zxMGnR6vXMIAsayiKHnIoVBDrNg/s1600/nitro+h%C3%B3a+amine+thom.bmp" title="nitro hóa amine thơm" width="400" /></a></div><h3 style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">III.Các yếu tố ảnh hưởng đến phản ứng</span></h3><h4 style="font-family: Helvetica, Arial;"><span style="background-color: white;">III.1:Ảnh hưởng của nhiệt độ</span></h4><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">-Nitro hóa là quá trình tỏa nhiệt mạnh.Bao gồm cả lượng nhiệt phản ứng và nhiệt tạo ra bởi sự pha loãng acid sulfuric bằng nước tạo ra trong quá trình phản ứng.</span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">-Tốc độ và hiệu suất của phản ứng phụ thuộc vào nhiệt độ</span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">-Nhiệt độ tối ưu của phản ứng phụ thuộc vào bản chất các chất được nitro hóa(-10 độ C-> 500 độ C)</span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;"> + Hydrocarbon mạch thẳng: 170 đọ C-500 độ C, cơ chế gố tụ do</span></div><div class="separator" style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;"> +Hydrocarbon thơm : -10 tới 170 độ C, nhiệt độ cao sinh ra nhiều tạp chất do phản ứng oxy hóa.</span></div><h4 style="clear: both; font-family: Helvetica, Arial; text-align: left;"><span style="background-color: white;">III.2:Tác dụng của khuấy trộn</span></h4><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Nitro hóa thường là phản ứng dị pha: Pha hữu cơ( chất cần nitro hóa) và pha acid(tác nhân nitro hóa). Do đó cần phải khuấy trộn manhj để tăng tiếp xúc và tránh quá nhiệt cục bộ.</span></div><h4 style="font-family: Helvetica, Arial;"><span style="background-color: white;">III.Ảnh hưởng của nước</span></h4><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">-Trong quá trình nitro hóa, nước được tạo ra làm giảm bớt nồng độ của acid sulfuric.</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">Phản ứng đạt tới cân bằng khi nồng độ acid giảm tới một giới hạn nào đó.</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">Mỗi chất khác nhau có giá trị khác nhau, <b>gọi là dung lượng khử nước của chất đó.</b> </span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;">Do đó cần tính toán lượng acid sulfuric cần dùng để pha hỗn hợp sulfo-nitric thông qua dung lượng khử nước của chất đó.</span></div><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"><br /></span></div><h2 style="font-family: Helvetica, Arial;"><span style="background-color: white;">B.Tài liệu tham khảo(References)</span></h2><h3 style="font-family: Helvetica, Arial;"><span style="background-color: white;">1.Acid sulfuric</span></h3><div style="font-family: Helvetica, Arial;"><span style="background-color: white;"> (<a href="http://p.pw/badBy0" rel="nofollow" target="_blank">http://p.pw/badBy0</a> and <a href="http://p.pw/badBy2" rel="nofollow" target="_blank">http://p.pw/badBy2</a>)</span></div><h3 style="font-family: Helvetica, Arial;"><span style="background-color: white;">2.Electrophilic substitution mechanism</span></h3><div><div style="font-family: Helvetica, Arial;"><a href="http://p.pw/badBy3" rel="" style="background-color: white;" target="_blank">http://p.pw/badBy3</a><br /><br /></div></div></div></div><table border="1" cellpadding="10"><tbody><tr><td><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbMSFIxRgrTU_mENvZ1gnXYNrX12n14tFBlwEXx-xkMfjDTcyonU0Y2DZe6q55Ht2JecO7Lk8UWGGuVv0UohEqBc8XvltVxncOuXo63cAMB_9vfGOzUi3YVrB9HJQEUzsv3txNjhaPJTY/s1600/hot.gif" imageanchor="1" style="font-family: Tahoma, Calibri, Verdana, Geneva, sans-serif; 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